Diode- puŵped Nd:YVO 4 Laser aŶd NoŶliŶear Optics ARMAN RASHIDI * , ABU FARZAN MITUL * University of New Mexico, Optical Science and Engineering (OSE), PhD Program *Corresponding author: arashidi@unm.edu, amitul@unm.edu Experiments Conducted during 03/29/2017 to 04/12/2017, Report Submission Date: 04/26/2017 ABSTRACT: A 1064 nm wavelength laser was obtained by pumping a Nd:YVO4 crystal using a 808 nm wavelength diode laser. A curved and a flat mirror were used to examine two different cavity mirrors. The Q-switching of this laser was realized using a saturable absorber. Second harmonic generation was performed to obtain both continuous wave and Q-switched 532 nm wavelength laser. OCIS codes: Q-switching; Solid State Laser; Second Harmonic Generation. 1. Introduction Diode- pumped solid-state lasers are efficient, compact, and all solid-state sources of coherent optical radiation. The latest advance in pumping technology is the diode laser. Diode-pumped neodymium lasers have operated at greater than 50 percent electrical to optical efficiency in a single spatial mode and with linewidths of less than 10 kilohertz. The high spectral power brightness of these lasers has allowed frequency extension by harmonic generation in nonlinear crystals, which has led to green and blue sources of coherent radiation. The diode laser efficiently emits optical radiation into a narrow spectral band. When the emission wavelength of the diode laser lies within the absorption band of the ion-doped solid-state laser medium, diode laser optical pumping can be very efficient. Flash lamp pumping efficiency is limited by the broad spectral emission of the lamp and the less efficient absorption of the lamp radiation by the solid-state laser medium. Moreover, the long upper-level energy storage times in solid-state lasers allow optical energy to be extracted in high peak power pulses under Q-switch operation[1]. In this lab a 808 nm diode laser was used to pump a Nd:YVO4 crystal lasing at 1064 nm wavelength. A Cr +4 :YAG was used to Q- switch the laser. Additionally, second harmonic generation was demonstrated to achieve green 532 nm laser under both continuous wave (CW) and Q-switching mode. 2. Laser components A. Nd:YVO4 Crystal The gain medium of the laser is Nd:YVO4 where Nd is the active material doped in the host YVO4. The emission spectra of Nd is shown in figure 1[2]. Fig. 1. Energy levels of Nd ions doped in YVO4 crystal. The YVO4 crystal (dL = 1 mm) is doped with Nd (1%) resulting in an absorption coefficient at the pump wavelength (808 nm) of  ≈ 3ͳ  −ଵ . The crystal plane facing the pump is anti-reflection (AR) coated for the pump wavelength and has a high-reflection (HR) coating for the fundamental laser wavelength, 1064 nm. This allows the pump wavelength to enter the gain medium while acting a s a mirror for the fundamental laser. The opposite crystal face is AR-coated for the fundamental laser wavelength which allow the fundamental wavelength to recirculate in the gain medium[2]. B. The diode laser pump source Research Article PHYC 476/477/302L Lab Report